1. Field of the Invention
The invention relates to headlamp assemblies for motor vehicles.
2. Description of the Prior art
The suspension systems of modern motor vehicles are relatively soft and have considerable travel for the comfort of the vehicle passengers but load variation varies the attitude of the vehicle body and therefore the angle of the vehicle headlamps with respect to the ground. Thus lights directed correctly when the vehicle carries the driver only may be raised by passengers and/or luggage in the rear of the vehicle to such an extent that they no longer provide proper illumination of the road ahead for the driver and may also dazzle drivers of vehicles travelling in the opposite direction. A number of arrangements have been proposed for enabling the driver to make instant adjustments to the angle of the vehicle headlamps from within the vehicle to cater for the effect of load variation in the vehicle. For example, U.K. patent specification No. 1,336,210 discloses an adjustment system comprising a single control cable actuated by a worm gear mechanism adjusted by a rotatable knob. The cable is connected to a relay member and further cables are connected between the relay member and lever systems which act on the headlamps to tilt the latter as the cable system is adjusted by the knob. The disadvantage of this system is that the multiplicity of cables make fine adjustment of the headlamps difficult and it is fine adjustments which are required to cater for the variations in the inclination of the vehicle body.
A further proposed solution to the problem is disclosed in U.K. patent specification No. 1,318,924 which describes an adjustment mechanism for vehicle headlamps comprising a control knob which rotates a notched wheel to rotate a bell-crank lever. The latter acts on a cable connected to a slider which rotates a rachet wheel which, in turn, moves a lever to tilt the lamp. This arrangement suffers from a number of disadvantages. Firstly, adjustment of the lamp is limited to half the number of notches on the ratchet wheel. Secondly, in certain positions of the mechanism pressure on one headlamp would tilt it to a new position out of phase with the other headlamp. Thirdly, the ratchet wheel can be rotated in one direction only and the headlamp must pass through its maximum tilt position before the tilt angle can be reduced.
It is an object of this invention to provide a headlamp assembly in which the tilt angle of the headlamp can be adjusted by a mechanism which overcomes the disadvantages of the mechanisms referred to above.